Former champions Stan Wawrinka and Rafa Nadal gave Australian Open organizers a massive boost on Tuesday when they both said they were looking forward to next week's season opening grand slam after battling long-term injuries.

The Australian Open has been hit hard by absences with Andy Murray, Serena Williams and Kei Nishikori among those to have withdrawn, while Nadal and Novak Djokovic have also been struggling with injuries, Reuters reported.

Wawrinka has been battling a knee injury and has not played since he was knocked out in the first round of Wimbledon last year, and the Swiss was one of the major question marks heading into the January 15-28 Australian Open.

"I'm really, really happy to be back on the Tour and seeing the sun," Wawrinka told reporters after an event with the tournament's ball kids at Melbourne Park on Tuesday.

“For me, the first thing is to play a match, to play a tennis match again. It's been many months out of the tour. It's not always the best when you are an athlete so I'm looking forward to it, enjoying the crowd. Still a lot to do but I'm feeling really positive so looking forward to starting."

It was naturally a welcome news to Australian Open director Craig Tiley.

"There's been a lot of questions and in fact this is the first time publicly in six months that he's said anything, so we are excited that he agreed to come here and do it with the ball kids," Tiley said. "So he's ready to play. I've watched him practice.

"Obviously to play best-of-five-set matches and to play seven of them in two weeks, he'd need to have a lot of things go his way. But, as he indicated this morning, he will be ready to play and it's great to see him out here."

Tiley's mood would have improved even further after Nadal returned to the court for an exhibition match at the Kooyong Classic.

The Spaniard had also been battling a knee injury and had not played since the season-ending ATP Tour Finals in London.

He withdrew from a warmup tournament in Abu Dhabi and last week's Brisbane International and had been concerned with his match fitness.

"It was a good test for me and good practice," the 16-times grand slam winner told reporters after his 6-4, 7-5 loss in which he appeared to be moving freely, if not a little rusty in his shotmaking.

"I'm good and I am here so that's good news and my idea is just to keep practicing the next couple of days to be ready for the beginning of the Australian Open.

"It was a long year last year so I started my preparation a little bit later than usual," Nadal said.

"It's good to start having the feelings of playing a match even if it's not official."